Furnace control



Sept. 7 1926.

E. M LE AN FURNACE CONTROL 4 SheetsShee'c 1 N VEN TOR.

76/3 ATTORNEYJ W//// Mm%6 Sept. 7 1926.

E. M LEAN FURNACE CONTROL INVENTOR.

Sept. 7, 192 1,599,137

E. M LEAN FURNACE CONTROL Original Filed June 25. 1920 4 Sheets-Sheet 3l I 4115 ,y;

IN VEN TOR.

W inuiam/ ATToRNEYs Sept. 7 1926.

E- M LEAN FURNACE CONTROL OriginaIFiled June 25, i920 4 Sheets- Sheet 4INVENTOR. M 711%? W 254A TTORNEYS Patented Sept. 7, 1926.

UNITED STATES PATENT OFFICE.

mumr MOLEAN, OF BROOKLYN, NEW YORK, ASSIGNOR TO THE ENGINEER COM- IPANY,OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

' FURNACE- CONTROL.

Original application filed June 25, 1920, Serial fuel fed through aburner or burners to the furnace, and the regulation of the draftpressure in the furnace chamber, the characteristic of the flow of fuelbeing preferably the pressure of volume of the fluid .fuel flowing tothe burner.

. The invention also contemplates an improved means for controlling theair fed to the furnace in such manner that a'uniform mixture of thefluid fuel and air is obtained for the varying conditions of the flamein the furnace chamher.

The invention consists in the improved means to be more fully describedhereinafter, and the novelty of which will be particularly pointed outand distinctly claimed.

I have fully and clearly illustrated certain embodiments of theinvention in the accompanying drawings to be taken as a part hereof, andwherein:

Figure 1 is a view in side elevation, partly in section, of a steamboiler furnace having one embodiment of my invention applied thereto;

Fig. 2 is a horizontal section on the line 22 of Fig. 1, with portionsbroken away to show other parts in section? Fig. 3 is a View in sideelevation, partly in section, of a steam boiler furnace showing anotherembodiment of my invention;

Fig. 4 is a transverse section through a controlling device employed inthe embodiment,shown in Fig. 3, wherein said device is operated by theVolume of oil fed to the burner'to control the air supplied for.combustion to the furnace;

Fig. 5 is a plan view of the lower portion or half of the device shownin Fig. 4;

Fig. 6 is a top plan view, partly in sec- No. 391,729. Divided and thisapplication filed October Serial No. 505,804.

tion, of the upper portion or half of theelement shown in Fig. 4;

Fig. 7 is a vertical central section through the pressure controlleddevice constituting one of the elements of the form of the inventionshown in Figs. 1 and 2, to control the air supplied to the furnace forcombustion, by the pressure of the fluid fuel fed to a burner;

Fig. 8 is a top plan view, partly in section, showing in detail certainof the elements in Fig. 7; Fig. 9 is a vertical longitudinal sectionthrough a regulator for controlling the quantity of fluid fuel fed tothe furnace in accordance with the steam pressure of the boiler, andalso to control the amount of atomizing steam fed to the burner toatomize the oil flowing therefrom into the furnace;

Fig. 10 is a detail view of a portion of the inlet air damperconnections shown in Figs. 1, 2 and 3;

Fig. 11 is a view in front elevation, partly in section, of a regulatorfor controlling the furnace gas pressure;

Fig. 12 is a central vertical section of the regulator shown in Fig. 11,and

Fig. 13 is a detail view, partly in section, showing the arrangement ofdampers for controlling access of air to the furnace chamber. I

I will first describe ,in detail the apparatus shown in the accompanyingdrawings and then, in connection with a description of the operationthereof, set forth the novel method, all of which constitute my inven=tion.

Referring to the drawings by characters of reference, and particularlyto Figs. 1 and 2, 1 designates a boiler furnace of any wellknownconstruction, and to which my invention is applicable, it beingunderstood that said furnace is slrown merely by way of example, andthat my invention is not limited to the type or construction of saidfurnace.

In the type of boiler furnace shown, said furnace is provided with sidewalls 2, 2, front wall 3, a rear wall 4, and a bridge wall 5, which,together with the front and side walls form a furnace chamber 7, the.top of the furnace chamber being formed by the lower surface of theboiler or boiler ture so as to provide a plurality of openings throughwhich air may flow from the chamber 9 to the furnace chamber 7, saidarea being .substantially coextensive with the. size of the flame whenthe burner 'is working at high pressure. By reference to Fig. 2, it willbe seen that the checker-work portion isof flaring form, the taperingsides of which are rovided by 'imperforate portions 11 of saidpartitions at the forward corners of the furnace, the outwardly inclinededges 12 of said imperforate portions defining the forward boundaries 0the flaring checker-work portion. In the present embodiment of saidflaring edges 12 extend from a point adjacent the center of the frontwall to a point substantially midwaythe length of the. side walls of thefurnace, so that the checker-work extends from said boundaries rearwardsto the bridge Wall lengthwise of the furnace, and

, the entire width of the furnace at points in the partition 8 conformssubstantially toi the maximum form of the flame in the furnace chamber.

The furnace is also provided with a su1t 5 able outlet stack 13 throughwhich the prodf ucts of combustion find exit, the area of 'f the passagethrough the stack. being con-" trolled by a suitable damper/14 pivoted,as;

at 15, on the stack, in any suitable manner.

The means for supplying fluid fuel to the furnace consists of a burneror nozzle 16 located preferably in the front portion of the furnacechamber above the partition 8 and central of the transverse width of thefurnace chamber, and over the forward portionof the openwork area ofsaid partition. This burner or nozzle may be of any well known type forfeeding fluid fuel in admixture with an atomlzing element, such as steamor air, to the furnace chamber. Oil or other fluid fuel is fed to thesaid burner from a pump 17 through a pipe 18 controlled by a shut-offvalve 19, and steam under pressure from the boiler is fed to the burnerthrough a pipe 20, the latter containing valves 21, 21. The quantity offluid fuel and atomizing steam flowing to the burner through pipes 18,20, is controlled by a 'regulator, shown generally at 22 in 1g. 1, andspecifically in Fig. 9, operating a source of steam at boiler pressure.

fby

valves in the fluid fuel and steam pipes, the

regulator forthis urpose, the same consisting of; a cylindrica chamber23 having diaphragm heads 24, 25 sealing the chamber, the latter beingconnected by a pipe 26 with Over thediaphragm 24 is a plate 27supporting a frame28 connected on its upper end, in any suitable'manner,to a valve body or casing 29 located in the steam pipe 20 between thevalves 21, as stated, said body having a valv'e seat 30 with whichcooperates a valve 31 connected to a stem 32 guided a. stufling box 33,and a sleeve 34, the latter being threaded in the said frame 28, asat35. The valve stem 32 is connected to a plate 36 resting on thediaphragm 24, heretofore described. Surrounding the stem 32 isan'expansion spring 37, the ends of which respectively abut the saidplate 36 and an abutment 38 resting against the lower end of said sleeve34, the function of said spring being to urge the valve 31 toward openposition in opposition to the pressure of steam within the chamber 23.The pressure of the spring 37 may be regulated by adjusting said screw34 and consequently the position of the said plate 38 so that the lattermay be adjusted relative to the plate 36fto compress or relieve thecompression "provided for regulating the quantity of uid fuel, andincludes a valve body or casing 39 in the pipe 18 having a seat 40having a passage controlled by a valve 41, the latter being connected toa. stem 42 guided through a stufling-box 43 corresponding to thestufiing-box 33, heretofore described, and supported by a frame 44' suported by a plate 45, similar to the plate 27 heretofore described. Thestem 42 is guided through an adjustable screw 46 threaded through aportion of the frame, as at 47, and carrying an abutment plate 48against which abuts one end of a spring 49 coiled about the said stem42, and the other end of which is connected to the plate 50 on the outerface of the diaphragm 25. This spring normally urges the valve 41towards open position in opposition to the steam pressure within thechamber 23 tending to close the valve. By adjustment of the elements 34and 47 heretofore described, the relative area of the opening in thesteam pipe and the oil supply pipe may be regulated in accordance with agiven steam pressure in order to determine the amounts or quantities ofoil and steam fed to the boiler;

Connected to the oil supply pipe 18, as at 51, is a pipe 52 leading to aregulator, shown generally at 53 in Figs. 1 and 2, which is actuated inaccordance with the pressure of the oil insaid pipe 18 to regulate thedampers, hereinafter described, so that the quantity of air fed to thefurnace will be varied in accordance with a charac teristic of flow ofoil fed to the boiler. in this instance, the characteristic of flowbeing the pressure of such oil. Said regulator will be specificallydescribed hereinafter.

The fluid fuel fed from the burner or nozzle 16 to the furnace chamber 7being under pressure is in the form which results in V a flame which iseither substantially cone-shaped or fan-shaped, according to the type ofburner employed. It is desirable that the airentering the furnacechamber be admitted over an area conformin as nearly as possible to theform or area 0 the-flame in order that the best results be obtained asregards complete combustion. My invention provides an eflicient meansfor regulating the area of air distribution, and for this purpose Iprovide means for controlling the area of the openwork partition of thepartition 8 through which the air flows from the space 9 to the chamber7 so that said area will conform substantially to the area of the flame,and will supply a quantity of air desirable for combustion. For thispurpose I divide the chamber 9 into a plurality of air chambers, eachpreferably having an independent air supply, and having outlets upwardinto the .furnace'chamber through that portion of the openwork partition8 immediately over the particular chamber beneath said partition. In thepresent embodiment, I preferably divide chamber 9 into three such airsupply chambers, and do this by providing two vertical partitions 54extending in a general direction lengthwise of the furnace and havingtheir inner ends closely adjacent each other to provide a passage, as at55, adjacentthe nozzle 16 from which point they flare outward to thepoint where they abut or join the bridge wall 5, as shown at 56. Theinner ends of said partitions 54 are connected by outwardly directed endartitions 57 with the side walls of the urnace, respectively. Thepartitions 54 and 57 extend from the floor of the furnace to theunderside of-the partition 8, so as to form three separate independentchambers. It will be seen that by the arrangement of partitions 54 and57, the space beneath the partition 8 is divided into a central flaringchamber 58 and two wing compartments '59, said central chamber beingapproximately the shape and area of being available for an increasedarea of the' flame when the burner is operated at relatively highpressures. It will thus be seen that I am'able to control the area ofthe partition 8 through which the air flows in order to conformsubstantially to the area of the flame when the burner is operated atdifferent pressures. As stated, I preferably provide independent meansfor controlling thesupply of air to each of the chambers 58 and 59, suchmeans preferably consisting of dampers 60, 61, 62, the same beingpi'voted.. respectively in the passage 55 between the inner ends of thewalls 54, and the dampers 61 and 62 being pivoted in openings 63 and 64in the said partitions 57.1 Inthe present embodiment, I provide meansfor automatically operating the said dampers in order to control the,supply of air to the chambers 58 and 59, in accordance with acharacteristic of the flow of oil to the burner. I desire it understood,however, that my invention, as regards the method of air distribution toconform to the area of the flame, it not limited to any particular meansfor controlling the amount of such supply, as such amounts may beregulated by either automatic or hand-control. In the present embodimentwhere the dampers are automatically controlled, the dampers 61, 62 aremounted on horizontal shafts 65 mounted in suitable bearings, carryinglevers 66, each of which is provided on its end with a weight 67, saidweight normally tending to rotate the shafts to move the dampers to openposition to increase the amount of air fed to the chambers 59. Thedamper 60 is mounted on a shaft 68 connected by a universal joint 69with one or both of the said shafts 65, so as to move all three of saiddampers in unison. The connection between the central damper 60 and thedampers 61 and 62 is so adjusted that when the dampers 61 and 62 areclosed, thecentral damper will be partially open, so as to admit air tothe central chamber 58, but as the dampers 61 and 62 are moved towardopen position, the damper 60 will be moved to increase the area of theopening controlled thereby to the chamber 58. Air is admitted to thefront portion of the furnace beneath the partition 8, and in front ofthe walls 57, through an air duct 70 in the front wall of the furnace.The duct 70'may be open to the atmosphere, as shown, or be connected toa source of draft under pressure, as for example, a blower. I willhereinafter describe two forms of automatic means for controlling thesaid dampers. I

The controller 53,11eretofore mentioned,

operates a flexible connection 71 extending upward over a sprocket 72 onone end of a horizontal shaft 73 in suitable bearings above the furnace,and thence downward and is connected to one of the' said. levers 66. Onthe opposite end of the shaft 73 is .a sprocket 74 over which extends asprocket chain 75, one end of which is connected to the other lever 66,the other end of said chain bearing a weight 76, by means'of which saidchain is maintained taut. The arrangement is such that when the pressureof oil flowing to the burner is increased, said regulator 53 will beactuated to move the dampers to increase the quantity of air flowing tothe air distributing chambers, whereas, on the other'hand, upon thereduction of the pressure of oil fed to the burner, said regulator willoperate to cause said dampers to be moved toward closed position toreduce the amount of air fed to the distributing chambers in accordancewith the pressure of oil fed to the burner, so that the air supplied anddistribution thereof is maintained commensurate for proper combustion.lhe regulator 53 may be of any well-known type which will" serve thepurpose and perform the functions set forth, but I prefer to employ whatis known on the market as the lWason compensating regulator which isshown in detail in Figs. 7 and 8 of the drawings. As this constructionis wellknown, I do not deem it necessary to describe the same withparticularity, but in order that the operation thereof may be understoodI briefly describe the construction as follows: 77 designates a platehaving a diaphragm chamber closed at its upper portion by a flexiblediaphragm 78 upon which rests a plate 79 upon which is mounted afulcrum80. The chamber 77* formed by the plate 77 and the diaphragm 78is connected to a pipe 52, heretofore described.

Supported over the diaphragm chamber is a frame 81 supporting adownwardly directed knife-edge fulcrum 82 against which bears a fulcrumpin 83 on one end of a lever 84, said lever also having a fulcrumbearing, as at 85, on the said fulcrum 80, so that said lever respondsto movements of the said diaphragm 78 in accordance with variations ofpressure in the diaphragm chamber 77. The outer end of the lever 84carries a weight 85 opposing the pressure exerted by the diaphragm 78tending to lift the lever 84. This lever 84 controls the flow of amotivefluid to a motor cylinder for operating the chain or. flexibleconnection 71, heretofore described. This motor cylinder is shown at 86containing a sliding piston 87 mounted on a piston rod 88 extendingthrough a stuffingbox 89 in one end of the cylinder and connected, as at90, to the said chain 71. Within the cylinder 86 are inlet ducts 91, 92,opening on opposite sides of thepiston 87 and communicating throughducts 93, 94, with a valveway 95, within which reciprocates adouble-headed piston valve 96 on a stem 97 extending through astufiing-box 98 on the casing of the piston valve and operable by meansof the lever 84, as will be presently described. Entering the valveway95 is a supply opening 99 leading from a suitable source of fluidpressure,'for example, water, and above and below the piston valve 96are exhaust chambers 100, 100 leading to an exit or exhaust 100", saidpiston valve 96 being operable to control the flow from the inlet 99,and to the exhaust chambers relative'to the said cylinder 86. When saidpiston valve is in the position shown in Fig. 7, flow of motive fluid iscut off both to and from the cylinder 86, the heads closing the ports93, 94. When the piston valve moves downward to uncover the port 93,flow will be permitted from the inlet 99 between the beads of the pistonvalve 96 to the passage 94, and thence through the passage 92 to thecylinder 86 below the piston 87, and at the same time the exhaust 1.00will be connected to the upper part of the cylinder 86 through thechamber 100 and the space above the upper head of the double-headedpiston valve 96. On the other hand, when the piston valve 96 movesupward, the upper portion of the cylinder 86 is connected to the inletthrough the passage 93 and the space between the heads of the pistonvalve 96, and the lower portion of the cylinder is connected to theexhaust through the duct 94, the chamber 100 and the duct or by-pass101, shown in dotted'lines leading to the exhaust 100". The piston rod97 is pivotally connected at its upper end, as at 102, to one end of alever 103, the opposite end of which is slotted, as at 104 (see Fig. 8),and-receives an eccentricopin 105 on a shaft 106 having bearing, as at107, in a bracket 108 on the cylinder 86, the opposite end of said shaft106 being rigidly connected to a lever 108, which, in turn, is pivoted,as at 109, to one end of a link 110, the other end of which is pivoted,as at 111, to the piston rod 88. The lever 103 is connected, as at 112,to one end of a link 113, the other end of which is connected, as at114, to the lever 84. When .the lever 84 raises the piston valve 96pressure is admitted to the upper end of the cylinder, as described, tomove the piston 87 downward; this causes a downward movement of the link110 which lowers the lever 108, and through connections 104, 105 raisesthe adjacent end of the lever 103, which, acting on the connection 112as a fulcrum, moves the doubleheaded piston valve 96 toward position toshut off the ports 93, 94. Upon a reduction of pressure in the chamber77, the weight 85 moves the lever 84 downward to thereby control the Howto admit pressure to the lower portion of the cylinder.

' v 86, causing the compensating mechanism to operate in the oppositedirection from that just described. In designingthis regulator, lengthof leverage between the pin 104 and the shaft 106 can be so proportionedthat the regulator may be caused to operate over any desired range ofpressures.

The invention also includes control of the furnace gas pressure so thatthe latter is maintained substantially constant for varying rate of airsupply, this being effected by controlling the outflow of gases from thefurnace. In order to accomplish this result, I provide the furnace withwhat is known as a balanced draft regulation operating in accordancewith the principle described in my prior United States Letters Patent vNo. 817,438, dated April 10, 1906, and No. 826,348, dated July 17, 1906,the regulator shown in the present application being of the same generalconstruction as shown and described in my prior Patent No. 1,071,771,dated September 2, 1913. This regulator is shown in detail in Figs. 11and 12. In these figures, 115 designates a rectangular frame set in anopening in one of the side walls of the furnace chamber and providing anopening between the furnace chamber and the external atmosphere. In thisrectangular frame is aranged a swinging rectangular plate 116 fulcrumedat a point adjacent its lower end, as at 117, to the side members of thesaid frame 115. This fulcrum is located preferably at or closelyadjacent the center of gravity of the plate, so that the said plate willremain stationary on its fulcrum at any point to which it may be moved.In order to insure the axis being through sion springs 121, 122, theformer being con-' n'ected at its lower end to a projection 123 on thelower end of the swinging. plate, and at its opposite end to anadjustable anchorage consisting of an eye or hook 124 on a threadedshank 124 extending slidably through a bracket 125 secured to the sideframe 115, said threaded shank being adjustably held by means of upperand lower nuts 126, whereby the tension of the spring 121 may beadjusted. The lower spring 122 is also connected at its upper end to thesaid arm or projection 123, and its lower end is connected to a hook oreye 127 having a threaded shank 128 extending slidably through anopening in a bracket 129 on frame 115, said shank being adjustablerelative to said bracket by means of nuts 130,

whereby the tension on said lower spring may be regulated. These springsserve to oppose the swinging movement of the plate and may be regulatedto balance the action of any draft pressure in the furnace. Themovements of the pressure regulator are employed to control the positionof the stack damper 14 so as to control the rate of outflow of furnacegases through the stack.

In order to accomplish this result, I. provide a pilot valve 131 havinan inlet 132 connected by a pipe 133 wit a source of fluid underpressure, and a combined inlet and outlet 134 connected by a pipe 135 tothe lower end of an operating cylinder 136 containing a piston 137connected to a piston rod 138, which in turn is connected by a flexibleconnection 139 with a lever arm 140 for operating the damper 14, saidflexible connection being passed over an intermediate guide pulley 141.The pilot valve is pro vided with a piston valve 142 connected looselyto a bracket arm 143 on the lower por-' tion of the swinging plate 116.The pipe 133 is connected by a .pipe 144 to the upper end of thecylinder 136,.above described. The pipe 133 contains hand valves 145,146, on opposite sides of the connection with pipe 144, and the pipe 135contains a hand valve 147. The pilot valve casing is provided with anescape opening 148 at its lower end.

The operation of said pilot valve is to control the flow of fluidpressure to and from the lower end of the cylinder 136 in order tooperate the piston 137 to control the damper 14. On the lever 140 is aweight 149 normally tending to hold the damper in open position. Theconstruction of this pilot valve is specifically shown in Fig. 11, but Ido not deem it necessary to describe the same with greater .detail, asit is of wellknown construction, and specifically does not form a partof my present invention.

The function of this regulator is to maintain a substantially constantpressure of furnace gases in the furnace chamber for the varying ratesof air supply entermg the furnace chamber for the purposes ofcombustion. In performing this function the regulator acts as follows:Should there be an increase of pressure in the furnace chamber abovenormal, the increase of pressure moves the plate 116 outward, operatmgthe ilot valve to control the flow of motor fluid to the cylinder 136'tocause the damper 14 to be moved to increase the rate of outflow of gasesthrough the stack, thereby reducing the pressure within the furnacechamber. If, on the other hand, there should be a decrease of furnacegas pressure below normal, the said plate 116 will be moved inward (tothe left in Fig. 12) by the external atmospheric pressure, whichmovement will operate the pilot valve to control the flow of fluid underthe piston to flow from the cylinder back through pipe 135 and outthrough the vent 1&8, there y causing the damper 14 to be moved toreduce the area of the stack outlet, and thereby increase the pressureof gases within the furnace. When the pressure is relieved under thepiston 137, as just described, said piston is moved downward by fluidpressure supplied to the upper end of the cylinder through the pipe 144,this pipe being in con stant communication with the source of fluidpressure. The use of the balanced draft regulator 116 is an importantfeature of my present invention, as it maintains a constant draftpressure in the furnace chamber. Therefore, for any given area of airdamper openings 55, 62, 63, there will be a given rate of flow of airthrough the damper opening 13, whereas, if the furnace pressure varied,the amount of air which would ass through a given area of damperopenlugs 55, 62, 63 would vary with the draft pressure in the furnace.As the area of air opening at 55, 62, 63 corresponds with the pressureof oil supplied to the burner, the dampers 60, 61 and 62 can be adjustedto be operated by the regulator 53 to give any desired rate of flow ofair for the corresponding pressure of oil to the burner.

Applicant is aware that it has been proposed to regulatethe airsupplydamper, and the stack damper in accordance with the variations ofthe pressure of oil to the burner, but such construction will notaccomplish the resultof applicants invention, because it will notmaintain a substantially uniform draft pressure in the furnace, due

to the fact that a given position of the flue damper in accordance withthe oil pressure a will not produce the same draft pressure in thefurnace chamber for all conditions of running the furnace. For a givenposition of the flue damper, the draft pressure in the furnace chamberwill vary with the draft of the chimney which varies with atmospherioconditions, and in plants where there are two or more furnaces connectedto one chimney, thedraft of the chimney is varied by the operation ofthe other furnaces, and the draft pressure in the furnace is also variedby the internal resistance of the furnace or boiler, due toaccumulations of flue dust and ashes. In all of these conditions myinvention maintains a substantially constant draft pressure in thefurnace chamber for all rates of combustion.

The maintenance of a substantially uniform pressure in an. oil burningfurnace is vastly more important than it is in a coal burning furnace,because the resistance of an oil burning furnace is very low,practically zero, whereas, the resistance of a bed of fuel is veryconsiderable. If th of an inch minus draft pressure would so ply therequisite amount. of air for an oi urning furnace or a fluid fuelburning furnace, and say 2 inches of draft pressure was necessarytosupply air to an ordinary coal burning furnace, a variation of th ofan inch in the draft pressure would double the variation in the airsupply to the fluid fuel burning furnace, whereas, 'it would only varythe air supply to the coal burning furnace 1/20th. It is thereforeapparent that a construction which provides a fixed position for, theflue damper corresponding to any given pressure of oil to the burnerwill not maintain a substantially uniform pressure of furnace gases forvarying rates of combustion, on account of the fluctuations in the draftof the chimney, due to atmospheric conditions, and due to variations infurnace conditions in other furnaces connected to the chimney, if any,and due to variations in resistance of the furnace and boiler on accountof accumulations of soot and ashes which vary from day to day. Thesevariations in a fluid burning furnace amount to as much as the totaldraft pressure necessary for varying combustion. Instead of operatingthe damper 14 to control the rate of outflow of furnace gases, anequivalent would be to employ an induced draft fan connected to thestack and driven by an engine, the controlling valve of which would bere ulated by the cylinder 136.

In ig. 3 I have shown another embodiment of the same broad invention,heretofore described, but instead of controlling the supply of airflowing into the furnace in accordance with the pressure of oil fed tothe burner, I effect such control in accordance with the rate of flow ofoil fed to the burner. In Fig. 3 I show the same structure as to thefurnace proper as shown in Figs. land 2, and also the same constructionof the means for maintaining a substantially constant pressure offurnace gases in the fire chamber, and therefore need not again describethese, as the previous description will be suflicient. In this form ofthe invention the burner or nozzle is shown at 16, the same beingsupplied with steam under pressure through a pipe 20, and by oil fedthereto by a pipe 52 supplied with oil under pressure from an oil pump17. The amount of flow of oil and atomizing steam may be controlled by aregulator 22 corresponding to the regulator 22, and operatin in the samemanner as heretofore descri ed. In this form of the invention, however,I provide means responsive to variations in the rate of flow to effectthe automatic operation of the dampers controlling the How of air intothe furnace, such regulator being.

Fig. 3, the regulator is interposed in the chamber, the upper half ofwhich is shown at 151, said members being connected by headed bolts 152and nuts thereon, said members clamping between a flexible diaphragm 153shutting off communication between said members, except as hereinafterdescribed. Integral with the member 130 is an inlet connection 154having a port 155 leading to an opening 156 through the flange of themember 150 leading into a passage 157 in the wall of the member 151,said passage 157 communicating with the space in said member 151 abovethe diaphragm 153. The connection 154: is connected to that portion ofthe pipe 52 nearest to and leading from the pump 17*. Connected to thelower member 150 is an outlet connection 158 (Fig. 5) opening into thelower chamber of the device below the diaphragm 153, said connection 158being connected to that part of the pipe 52* leading from said regulatorto the burner 16". The chamber in the upper member 151 above thediaphragm 153 opens through a port 159 into a valve casing 160,preferably formedv integral with the member 151, and containing atapered turn-plug valve 1.61, the latter having a 'port 162 adapted tocommunicate with the said port 159,' and leading to the internal bore163 of the valve, which in turn communicates with a passage 164: leadinginto the member 150 beneath the diaphragm 153. In order to provide for atight fit, the valve 161 is preferably tapered and fitted to acorrespondingly tapered bore in the casing 160 and is urged to its seatby a spring 165 surrounding a stem 166 on said valve, and at one endabutting a packin gland 167 threaded into the casing 160, and

- at its other end abutting the upper end of the said valve 161.

The valve is provided with a head 168 adapted to beengaged by a Wrenchor other suitable means by which it may be rotated. Connected to thediaphragm 153, in any suitable manner, as at 169, is one end 170 of arod 171 extending vention shown in Figs. 1 and 2. The means forconnecting the rod 171 to the diaphragm, consists of dished plate 170having a flange 170 secured by a fluid-tight joint to the lower face ofthe diaphragm by means of screws 170 extending through said flange,packing washers 170 between the flange and the diaphragm, and threadedinto a washer or ring 170 on the upper side of the diaphragm. The dishedportion of the plate 17 0 extends upward through a central opening inthe diaphragm and has a central opening 170 through which the rod 171extends, the rod having beneath said plate an enlargement or head 171 ofgreater diameter than, the opening in said plate so that the rod andplate are connected. The under side of the plate is closed againstleakage by a plate 171 held in placeby the screws 17 0. On the casing ofthe regulator is a bracket 17 8 between which and the lever 174 issuitably supported and held a compression spring 179 tending to move thelever 174: upward. One end of the spring 179 is seated in a spring seat180 supported on one end of an adjusting screw 181 threaded through thebracket 17 8, and by means of which the resistance of the spring 179 todownward movement of the lever 174: may be regulated. The screw 181 maybe locked in adjusted position by a jam nut 182 threaded thereon.Supported by the bracket 178 is a scale member 183 having a scale 184calibrated to indicate gallons per minute or other unit of time of flowof fuel to the burner, the upper edge of said lever 1741 cooperating asa pointer with said scale. It will be understood that said scale may becalibrated to indicate any useful information measureable by position ormovement of the diaphragm 153. The operation of this device is as"follows "The fluid fuel enters the connection 15 and flows through ports155 and 157 into the space above the diaphragm 153, thence through theport 159 and valve ports 162, 163. and port 16& into the space beneaththe diaphragm 153, from which space itflows outward through pipe 52 tothe burner 16. The valve 161 is operable to cause a restriction to theflow between the upper and lower chambers of the regulator having thediaphragm between them, so as to create a upward through a stuffing-box172 in the (reduction in pressure in the chamber beupper wall of themember 151, the upper end of said rod 171 being pivotally connected, asat 173, to a lever 174, one end of which is pivoted, as at 175, to themember -151, and the other end of which is connected to a flexibleconnection 176 passing upward over a pulley 177, and thence downward tothe levers 66 on the shafts operating the dampers 60, 61, 62 in the samemanner as described with reference to the form of inneath the diaphragm,this reduction in pressure being employed to cause movement of thediaphragmto operate the lever 174: to control the dampers. It will beunderstood that the valve 161 is set so. as to result in a restrictiongiving the desired difference in ressure between the fluid in the twochamers, and that any variations of this difference of pressure, due tofluctuations in the volume of flow during the operation of the furnace,will operate the diaphragm to correspondingly regulate the position ofthe dampers G01 61, (32. The chambers on op site sides of the diaphragm153 are pre erably designed so as to be of equal volume andsymmetricalin shape so that the effect of the velocity head of the fluid flowingthrough them will not tend to move the diaphragm, any action of thevelocity head on one side of the (liaphragm being counterbalanced by asimilar action on the other side.

The result of the neutralizing or counterbalancing of the velocity headin the two chambers, is that the diaphragm is actuated by the differencein static pressure due to the restriction in the passage between the twochambers. It will thus be seen that when the steam pressure drops, thevalve 22 will be operated to increase the amount of fluid flowing fromthe pump 17 through the regulator 53 to the burner, and that the greaterthe amount of oil flowing through the regulator, the greater will be thedifference in pressure between the fluid above the diaphragm 153 andthat below said diaphragm, resulting in the excess-pressure above thediaphragm moving the rod 171 to swing the lever 174 to operate thedampers 60, 61, 62 to increase the amount of air snpply flowing into thefurnace. If the boiler pressure increases, the opposite operation fromthat described takes place, that is, the regulator 22 operates to reducethe amount of fluid flowing through the regulator to the burner, which iis followed-by a reduction of the difference in pressure between the oilabove the diaphragm 153, and below said diaphragm, permitting thediaphragm to move upward, whereupon the spring 179, actingagainst thedifference of ressure in the regulator, anoves the lever 1? dampers (S0,61, 62 to shut off or reduce the supply of air fed into the furnace.Whether operable by the pressure of the fuel as illus 'trated inFigure-1, or by the rate of flow thereof, as illustrated in Figure 3,the means controlling the area of the open-work partition through whichthe air flows, is controlled in accordance with variations inacharacteristic in the flow of the fluid fuel.

Inasmuch as the balanced draft regulator acts in the same manner asdescribed with reference to the form of the invention shown in Figs. '1and 2, it is not necessary to repeat that description here. The valve161 can be so adjusted that the variations in differ ence of pressuredue to variations of volume of flow whichcause the travel of the rod171, can be made to give the dampers 60, 61 and 62 the desired positionfrom minimum desired opening to maximum desired opening, correspondingto minimum flow of fluid fuel to maximum flow of fluid fuel.

This ap lication is a division of my application Senal No. 391,779,filed June 25, 1920.

4 upward to control the- What I claim and desire to secure by LettersPatent of the United States is 1. In a fluid fuel-fired furnace, incombination, a furnace chamber, a burner for feeding fluid fuel thereto,an openwork partition, means for supplying air to said chamber throughsaid partition and means for automatically and progressively varying thearea of the openwork partition through which the air flows.

2. In a fluid fuel-fired furnace, in. combination, a furnace chamber, aburner for feeding fuel thereto, an openwork partition, means forsupplying air to said chamber through said partition and means operablein accordance With variations in a characteristic of the flow of thefluid fuel to the furnace for automatically and progressively varyingthe area of the openwork partition through which the air flowstransversely of the direction of the flame.

3. In a fluid-fuel fired furnace, in combination, a furnace chamber, aburner for feeding fluid fuel thereto, an openwork partition, means forsupplying air to said chamber through said partition and .means operablein accordance with variations in a charac teristic of the flow of thefluid fuel for automatically and progressively varying the area of theopenwork partition through which the air flows to conform to the area ofthe flame.

4. In a fluid fuel-fired furnace, in combination, a furnace chamber, aburner for feeding fluid fuel thereto, an openwork partition beneathsaid burner, means for supplying air to said chamber through saidpartition, partitions dividing the space beneath said openwork partitioninto a plurality of chambers transversely of the direction of the flame,and means operable in accordance with variations in a characteristic ofthe flow of the fluid fuel for automatically and progressively varyingthe flow of air through said chambers.

5. In a fluid fuel-fired furnace, incombination,a furnace chamber, aburner for feeding fluid fuel thereto, an openwork partition beneathsaid burner, partitions dividing the space beneath said partition into aplurality of chambers transversely of the direc-' tion of the flame,said chambers being independently open to air supplies, and meansoperable in accordance with variations in a characteristic of the flowof the fluid fuel for controlling the flow of air through said chambers.

6. In a fluid fuel-fired furnace, in combination, a furnace chamber, aburner for feed- .ing fluid fuel thereto, an openwork partition beneathsaid burner, partitions dividing the space beneath said first namedpartition into chambers at least one of which flares outward in thedirection of the fuel feed from the burner, means for supplying air tosaid wearer last named chambers and thence through said openvvorkpartition to said furnace chamber, and means'operable in accordance withvariations in a characteristic of the flow of the fluid fuel forcontrolling the flow oi air through said chambers.

71in a fluid fuel-fired furnace, in combination, a furnace chamber, aburner for feeding fluid fuel thereto, an openwork partition beneathsaid burner, partitions dividing the space beneath said openworkpartition into a plurality of chambers transversely of the direction ofthe flame, damper means controlling the flow of air to said chambers,and means responsive to variations in a characteristic of the flow ofthe fluid fuel to the burner to control said damper means.

8. In a fluid fuel-fired furnace, in combination, a furnace chamber, aburner for feeding fluid fuel thereto, an openwork partition beneathsaid burner, partitions dividing the space beneath said openworkpartition into a central chamber and at least two side chambers one oneach side of the central chamber, said partitions extending in ageneraldirection lengthwise of the flame, damp-- er means controllingthe flow of air to said chambers, and means responsive to variations ina characteristic of the flow of the fluid fuel to the burner to controlsaid damper means, the damper for the central chamber being open in oneposition While those for the side chambers are closed.

In testimony whereof I have hereunto signed my name.

EMBURY MGLEAN.

